As a railcar bogie, there exists a steering bogie capable of changing directions of wheelsets in a yawing direction. Known as one example of such steering bogie is a steering bogie of PTL 1. The steering bogie of PTL 1 includes a link mechanism (Z link), and the Z link includes a vertical link and two horizontal links. The vertical link is attached to a bogie frame so as to be turnable and is coupled to a carbody through a parallel link. Further, the two horizontal links are attached to the vertical link. The two horizontal links extend from the vertical link to one side and the other side in a forward/rearward direction and are attached to respective axle boxes provided at respective wheelsets.
When the steering bogie 1 configured as above travels through a curved line, the carbody and the bogie swing relative to each other, and the vertical link turns. With this, the two horizontal links move the axle boxes in such directions that the axle boxes get close to each other or separate from each other. Thus, a wheel base at a curved line outer rail side is increased, and a wheel base at a curved line inner rail side is decreased. As a result, the wheelsets can be steered, and this can change the directions of the wheelsets in the yawing direction.